Selective-laser melting machines consist of a single high-power laser and a scanner to scan the laser over the area to be illuminated. In such machines the laser and the scanner are arranged outside of a process chamber and the laserlight can pass through an entrance window into the process chamber that contains a building area. To increase the processing speed, it is desirable to have a printing head with several independent channels i.e. an addressable array of lasers covering a significant part of the area. Preferably, the printing head covers the full width of the area to be printed with one addressable laser source per pixel, so that the print head needs to be moved only in one direction. Reliability and service costs of such addressable arrays may be an issue.
US 2005/0151828 A1 discloses a device for xerographic laser printing. The xerographic printing system has a laser printbar imager assembly including a plurality of micro-optic light emitting arrays. The micro-optic light emitting array includes a plurality of vertical cavity surface emitting lasers, where each vertical cavity surface emitting laser is focused with a micro-optic element.